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    <title>Document</title>
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    <script>
      let p = new Promise((resolve, reject) => {
        //1. 先改变状态, 再指定回调
        // resolve("OK");
        reject("Error");
      });

      //可以只指定成功的回调  名词儿:  异常穿透
      p.then((v) => {
        console.log(111);
      }).then((v) => {
        console.log(222);
      }).catch(reason => {
        // try...catch 
        console.warn(reason);
      });
    </script>
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